In New Mexico, Hispanic male mortality rates for lung cancer and for chronic obstructive pulmonary disease are markedly lower than rates for non-Hispanic (Anglo) whites. For females, overall rates for Hispanics and Anglos are similar but the patterns of age-specific rates differ. Cigarette smoking practices may partially explain these differences. To further characterize the epidemiology of respiratory diseases among Hispanics, we propose to conduct a prevalence survey of residents of Belen, New Mexico. This community, located near Albuquerque, has a stable Hispanic population of approximately 3,900. We will identify all Hispanic residents in a preliminary census and anticipate that approximately 2,700 children and adults will subsequently participate. Survey procedures will include completion of standard respiratory symptoms questionnaires, a household questionnaire directed at environmental exposures and validation of ethnicity, spirometry, and measurement of end-tidal carbon monoxide and salivary thiocyanate. The analyses will be primarily directed at describing the prevalence of respiratory symptoms and diseases in Hispanics; determining risk factors for respiratory disease in this population; and developing prediction equations for spirometric parameters in Hispanics. The household based design will also permit assessment of familial aggregation of respiratory diseases and of lung function level. A comprehensive cigarette smoking history will be obtained so that the effects of various types can be compared. The proposed investigation should provide previously unavailable information concerning respiratory diseases and lung function in Hispanics.